The subject matter of the invention relates to a vehicle wheel for a vehicle.
DE 101 61 869 A1 shows a vehicle wheel having a plurality of spokes, lamellae, blades or similar, which are arranged on an outer side of the vehicle wheel and connect a rim base to a slide element. Between the spokes, lamellae, blades or similar, openings or spaces are provided which can be covered or closed as a result of a movement of the vehicle wheel. A centrifugally-controlled kinematic system is provided for this purpose, by means of which corresponding cover elements or mass elements are moveable.
Furthermore, it is known that a vehicle wheel having a strong three-dimensional design and strong “cupping” gives a vehicle a powerful athletic appearance. The term “cupping” in the context of a vehicle or a wheel rim is understood to mean that on the outer side, at least in the central region near the hub, a recess, depression, indentation or similar is provided, wherein this shape can be formed, for example, by several spokes, lamellae or blade elements or similar.
At high speeds, however, air resistance contributes significantly to fuel consumption. Here, a strongly cupped vehicle wheel has considerable disadvantages with regards to air resistance.
EP 1 319 526 A2 shows a vehicle wheel which comprises a rim and a hub provided in the central region, wherein the rim and hub are connected to each other by means of spokes which are arranged distributed over the circumference. Openings are provided between the spokes, which openings can be at least partially covered by means of a slide element that is arranged on an outer side of the vehicle wheel and is formed to be similar to a disc-shaped hub cap. For this purpose, the slide element is shiftable outwards in the direction of the wheel axis of rotation from an inner position in which the openings are covered into an outer position in which a gap is created between the disc-shaped slide element and the vehicle wheel via which a cooling air flow from a vehicle brake reaches the outside. By means of this slide element, the outer appearance of the vehicle wheel, in particular the cupping of the vehicle wheel, is hardly changed regardless of the vehicle speed.
The object of the invention is thus to create a vehicle wheel of the aforementioned type, which has improved aerodynamic properties at high speeds with a strong cupping at low speeds.
In order to create a vehicle wheel of the aforementioned type, which has improved aerodynamic properties at high speeds with a strong cupping at low speeds, it is provided according to the invention that at least some of the spokes, lamellae, blades, wheel segments or similar are hinged to the slide element and adjustable together with the slide element which is axially shiftable in the direction of the axis of rotation of the vehicle wheel. In the inner position, the distance of the slide element from a longitudinal central axis of the vehicle is smaller than in the outer position. The displacement of the slide element is therefore carried out depending on speed in the vehicle transverse direction and thus also in the radial direction relative to the vehicle longitudinal central axis.
The hinging of the spokes, lamellae, blades, wheel segments or similar on the slide element results in the spokes, lamellae or similar being positioned or displayed during the outward displacement of the slide element, which leads to a reduction in the cupping of the vehicle wheel. This produces an especially simple and effective opportunity to improve the flow resistance of the vehicle wheel on its outer side.
In an especially advantageous embodiment of the vehicle wheel, it is provided that at least some of the spokes, lamellae, blades, wheel segments or similar are pivotably mounted on an axis (a) which is fixedly arranged on the vehicle wheel. The spokes, lamellae, blades, wheel segments or similar are therefore placed outwardly during adjustment of the central slide element and thus pivot around the axis (a) of their respective outer support point, such that they occupy an overall substantially perpendicular placement when the slide element is arranged in an outer position, in which position the vehicle wheel has no or only a low cupping on its outer side. In this placement, the spokes, lamellae, blades, wheel segments or similar are therefore at least substantially aligned in the vertical direction (Z direction) of the vehicle and thus perpendicular to the road.
It is therefore provided according to the invention that the vehicle wheel is equipped with a mobile, in particular translationally displaceable, slide element. Preferably, this slide element is shiftably mounted in the direction of or parallel to the axis of rotation of the vehicle wheel. The axis of rotation of the vehicle wheel and the longitudinal central axis of the slide element are preferably aligned with each another or are coincident. In this case, the slide element is therefore arranged concentrically to the vehicle wheel axis of rotation or is shiftable coaxially to this axis.
In a preferred embodiment of the vehicle wheel, it is provided that a corresponding kinematic system is provided on the vehicle wheel for this purpose, such that the slide element of the vehicle wheel is outwardly shiftable from a first position in which the rim has a correspondingly large cupping into a second position, in order to at least reduce the cupping of the rim or alternatively to fully remove it. A vehicle wheel which is aerodynamically adapting and thus actively optimizable during vehicle operation is hereby created.
In a further embodiment of the invention, the kinematic system comprises at least one centrifugal force actuator, by means of which the central slide element is adjustable between the inner position and the outer position. The activation of the displacement movement of the slide element and the forces required for this thus result from the centrifugal forces of the at least one centrifugal force actuator. In this respect, it has been found to be advantageous when an automatic adjustment of the slide element from the inner position in the direction of the outer position is carried out at a correspondingly high peripheral speed of the vehicle wheel. By using centrifugal force for activation and adjustment of the slide element provided on the vehicle wheel, the system is thus independent of electricity and electronics. Active actuators, control devices, radio devices and the like can thus be avoided when there is centrifugal force control. Use independent of vehicle size, series and type is possible. The adjustment of the activation speed is preferably carried out via the lever lengths or the size of the mass. It should, however, be noted that a system comprising an active actuator or similar could also be used, alternatively or in addition to the use of centrifugal force.
In a further advantageous embodiment of the invention, the kinematic system comprises at least one return element, in particular at least one return spring, by means of which the slide element can be automatically returned between the outer position and the inner position. This therefore also produces a system which is independent of electricity and electronics. The slide element thus preferably automatically returns from the outer position in the direction of the inner position when the peripheral speed of the vehicle wheel falls below a specified level.
A further preferred embodiment of the invention is characterized in that the spokes, lamellae, blades, wheel segments or similar can be folded from the slide element around an axis of rotation in the vicinity of a rim flange. It is thus possible, for example, for the spokes, lamellae, blades, wheel segments or similar to be folded outwards flush to the wheel scythe, whereby the cupping is reduced and a virtually flat vehicle wheel having an aerodynamically optimized contour is produced.
If, in a further embodiment of the invention, the spokes, lamellae, blades, wheel segments or similar are received by a carrier wheel, a separate component is thus created which, for example, can be attached to spokes of the vehicle wheel and/or its rim. A virtually flat vehicle wheel having an aerodynamically optimized contour can thus be achieved by the reduction in cupping. The system according to the invention can therefore be both part of the vehicle wheel itself and a separate device, which can subsequently be attached—in the manner of a hub cap—to the vehicle wheel.
Finally, it has been shown to be advantageous when the wheel segments are formed as surface elements between the spokes, lamellae, blades or similar. These surface elements, which, for example, each cover the free space between two adjacently arranged wheel segments, together with the spokes, lamellae, blades or similar, enable a flat shape of the vehicle wheel on the outer side, similar to a disc wheel.
Further details of the invention arise from the following description of preferred exemplary embodiments and with the aid of the drawings.